The term “Ethernet” refers to a family of local area network (LAN) implementations that includes several principal categories: (i) Ethernet and IEEE 802.3 are LAN specifications that operate at about 10 megabits per second (Mbps) over, for example, thick and thin coaxial cable, or twisted pair cable; (ii) 100-Mbps Ethernet, a single LAN specification that operates at 100 Mbps over fiber and twisted-pair cables (alternatively referred to as Fast Ethernet because it is 10 times faster than the older 10 Mbps standard) and is defined in IEEE standard 802.3u which is incorporated herein by reference in its entirety; (iii) 1000-Mbps Ethernet, a single LAN specification (alternatively referred to as Gigabit Ethernet, GbE, or GigE) that operates at 1000 Mbps or 1 gigabits per second (Gbps) over fiber and twisted-pair cables; and 10 Gigabit Ethernet, a single LAN specification (alternatively referred to a 10 GbE or 10 GigE) that operates at 10 Gbps over fiber or twisted-pair cables. Ethernet has survived as an essential media technology because of its tremendous flexibility and its relative simplicity to implement and understand. Although other technologies are touted as possible replacements, network managers continually turn to Ethernet and its derivatives as effective solutions for a range of implementation requirements.
Differences between Ethernet and IEEE 802.3 LANs are subtle. Ethernet provides services corresponding to Layers 1 and 2 of the OSI reference model. IEEE 802.3 specifies the physical layer (Layer 1) and the channel-access portion of the link layer (Layer 2), but does not define a logical link control protocol. Both Ethernet and IEEE 802.3 are typically implemented in hardware. The physical manifestation of these protocols is either an interface card in a host computer or circuitry on a primary circuit board within a host computer. IEEE 802.3 specifies several different physical layers, whereas Ethernet defines only one. Each 802.3 physical layer can be associated with a name that summarizes characteristics of the physical layer. For example, 10Base2 is the name of a physical layer that is similar to Ethernet and that has characteristics including a 10 Mbps data rate, a baseband signaling method, a maximum segment length of 500 feet, a 50-ohm coax connection media, and a bus topology. The moniker 1000BASE-X is used in industry to refer to a physical device (PHY) layer that transmits data at a rate of 1 Gbps over fiber. 1000BASE-T refers to a physical layer that transmits data at a rate of 1 Gbps over twisted pair copper wires. 10GBASE-R refers to a physical layer that transmits data at a rate of 10 Gbps over fiber, and 10GBASE-T refers to a physical layer that transmits data at a rate of 10 Gbps over twisted pair copper wires.
As Ethernet standards have evolved over time, the speed at which data is transmitted via an Ethernet network has increased, usually by a factor of ten as a new standard is developed.